Environmental challenges related to offshore mining and ...€¦ · Environmental challenges...

RAPPORT

M-532 | 2016

Environmental challenges related to

offshore mining and gas hydrate extraction

Environmental challenges related to offshore mining and gas hydrate extraction | M-532

KOLOFON

Utførende institusjon

Centre for Geobiology and Centre for Deep Sea Research, University of Bergen

Oppdragstakers prosjektansvarlig Kontaktperson i Miljødirektoratet

Hans Tore Rapp Ingrid Handå Bysveen

M-nummer År Sidetall Miljødirektoratets kontraktnummer

532 2016 28 14080454

Utgiver Prosjektet er finansiert av

Miljødirektoratet Miljødirektoratet

Forfatter(e)

Bernt Rydland Olsen, Ingeborg Elisabeth Økland, Ingunn Hindenes Thorseth, Rolf Birger Pedersen,

Hans Tore Rapp

Tittel – norsk og engelsk

Miljøutfordringer relater til utvinning av mineraler og gass-hydrater fra havbunnen

Environmental challenges related to offshore mining and gas hydrate extraction

Sammendrag – summary

Denne rapporten oppsummerer dagens kunnskap om forekomster av mineraler og gasshydrater på

havbunnen i norske farvann, og gir en oversikt over dagens kunnskap og kunnskapshull relatert til

biologiske samfunn (arter/naturtyper) som kan forventes å bli påvirket som følge av framtidig

utvinning av mineraler og gass-hydrater fra havbunnen.

This report summarizes the current knowledge of known resources of deep-sea minerals and gas

hydrates in Norwegian waters and the biology and ecosystems represented in such areas. The major

gaps of knowledge regarding the biodiversity is identified; the distribution, function as well as the

goods and services provided by these ecosystems.

4 emneord 4 subject words

Mineralutvinning, gass-hydrater, hav,

miljøeffekter

Mining, gas hydrate, sea, environmental

impacts

Forsidefoto

Centre for Geobiology and Centre for Deep Sea Research, University of Bergen


Innhold

1. PART A - Mineral Resources ............................................................................... 6

1.1 Geographical location of known mineral resources of potential commercial value in

Norwegian waters .......................................................................................... 8

1.2 Seafloor Massive Sulphide-deposits – Vent sites, threats and environmental impact .. 10

1.2.1 Vent sites .................................................................................... 10

1.2.2 Threats and environmental impact...................................................... 15

1.3 Environmental considerations and restitution potential .................................... 16

1.3.1 Before mining ............................................................................... 16

1.3.2 During mining ............................................................................... 17

1.3.3 Restitution potential ....................................................................... 17

1.4 Knowledge status and mapping .................................................................. 18

2. PART B - Gas hydrates ................................................................................... 21

2.1 Geographical location of known gas hydrates of potential commercial value in

Norwegian waters ........................................................................................ 21

2.2 Gas hydrate habitats, threats and environmental impact .................................. 22

2.2.1 Habitats ...................................................................................... 22

2.2.2 Threats and environmental impact...................................................... 24

2.3 Environmental considerations and restitution potential .................................... 25

2.3.1 Before exploitation ........................................................................ 25

2.3.2 During exploitation ......................................................................... 26

2.3.3 Restitution potential ....................................................................... 26

2.4 Knowledge status and mapping .................................................................. 26

2.4.1 Summary of knowledge gaps ............................................................. 26

3. References ................................................................................................. 28


Sammendrag

Denne rapporten oppsummerer dagens kunnskap om forekomster av mineraler og gasshydrater

på havbunnen i norske farvann, og gir en oversikt over dagens kunnskap og kunnskapshull

relatert til biologiske samfunn (arter/naturtyper) som kan forventes å bli påvirket som følge

av framtidig utvinning av mineraler og gass-hydrater fra havbunnen. Rapporten gir en oversikt

over hva som gjør disse samfunnene spesielle, hvilke trusler representerer denne typen

næringsaktivitet i slike områder og hvilke hensyn som bør tas, før, under og etter

næringsaktivitet.

Langs den arktiske midthavsryggen og langs den norske kontinentalsokkelen og

kontinentalskråningen finnes det en rekke unike men dårlig kjente økosystem og naturtyper.

Områder med varme og kalde gassoppkommer og områder med metanhydrater er ofte

kolonisert av svært spesialiserte organismer, og gir opphav til en rekke sårbare marine

økosystem i områder som ofte sammenfaller med fiskerier, olje- og gassutvinning og fremtidig

utvinning av mineralressurser. Selv om disse områdene er kjent for sitt biologiske mangfold,

økologiske betydning og bioteknologiske potensiale, har det så langt vært begrenset

forsknings- og forvaltningsfokus på disse økosystemene i norske havområder.

Summary

This report summarizes the current knowledge of known resources of deep-sea minerals and

gas hydrates in Norwegian waters and the biology and ecosystems represented in such areas.

The major gaps of knowledge regarding the biodiversity is identified; the distribution,

function as well as the goods and services provided by these ecosystems. It also aims to

identify the main threats and impacts posed upon these ecosystems by future gas

exploitation, and mining of deep sea minerals and outlines environmental elements to be

considered before, during and after mining/extraction activities.

A high variety of unique and by far unexplored extreme deep-water ecosystems and nature

types are found in along the Arctic mid-ocean ridge and along the Norwegian continental shelf

and slope. Areas with hydrothermal vents, methane seeps/areas with methane hydrates often

host assemblages with very specialized biota, and form a variety of vulnerable marine

ecosystems in areas which often coincide with fishing, oil and gas exploitation, as well as

future mining of deep sea minerals. Even though their biodiversity, ecological importance and

biotechnological potential is assumed to be high, these ecosystems have so far received

relatively little scientific or conservation attention in Norwegian waters.


Report rationale Mineral deposits and gas hydrates are presently non-utilized resources, but may be subject to

commercial exploitation in the future. However these resources are often found in very

inaccessible and poorly known areas. These areas host ecosystems that are potentially

vulnerable to the physical impact caused by utilization of these resources. Therefore it is

instrumental to conduct thorough Environmental Impact Assessments (EIA) and that the EIAs

are based upon solid basic science. This report aims to provide an overview of current

knowledge and gaps regarding biological communities from both deep-sea mineral

deposits/hydrothermal vents and gas hydrates. Furthermore it aims to provide information that

can serve as a first step towards a knowledge-based management plan and future EIAs for areas

hosting these resources.

Report limitations: The report covers the Norwegian Economical Exclusive Zone (EEZ), Svalbard EEZ as well as areas

within the Extended Continental Shelf and international waters along the Arctic Mid-Ocean

Ridge (AMOR). Norway regulates the Norwegian national waters in addition to the Svalbard

waters, while the International Seabed Authority (ISA), established under the United Nations

Convention on the Law of the Sea (UNCLOS) article XI (1994), regulates the international waters

(Allen 2001). Furthermore, the report is restricted to known resources of Seafloor Massive

Sulphide deposits (SMS-deposits) from active hydrothermal vents and known gas hydrates

resources along slopes of the Norwegian coast and western part of Svalbard. The report does

not cover polymetallic crust resources discovered along the Jan Mayen Ridge and the Jan Mayen

Fracture Zone as there yet is very limited knowledge about these resources and the associated

biota.

Within Norwegian waters it is primarily the SMS-deposits along the Arctic Mid-Ocean Ridge that

have been given attention. From that area four active and two inactive vent sites with SMS-

deposits are known. The report will focus on these habitats, with special emphasis on the active

localities. Climate change aspects of the gas hydrate resources will not be discussed, although

there are concerns regarding the utilization of methane from a climate change perspective.

As SMS-deposits and areas with gas hydrates are two very different ecosystems these will be

treated separately in two different chapters (part A and B).


Definitions/abbreviations:

AVF -Aegir’s Vent Field

Ag -Silver

AMOR -Arctic Mid-Ocean Ridge

Au -Gold

Baseline -Natural conditions, often presented as a time series

Breccia -Breccia is a clastic sedimentary rock similar to conglomerate that can

be formed in a variety of ways

Chalcopyrite -Copper Iron sulphide

Co -Cobolt

Cu -Copper

EIA -Environmental Impact Assessment

EEZ - Economical Exclusive Zone

Fe -Iron

Galena -Lead sulphide

Hyaloclastite -hydrated tuff-like breccia

ISA -International Seabed Authority

JMVF -Jan Mayen Vent Field

LCVF -Loki’s Castle Vent Field

Marcasite -Iron sulphide

Mn -Mangan

Pb -Lead

Pyrite -Iron sulphide

Pyrotitt -Iron sulphide

SMS-deposits -Seafloor Massive Sulphide deposits

Sphalerite -Zink sulphide

SSVF -Seven Sisters Vent Field

UNCLOS -United Nations Convention on the Law of the Sea

Zn -Zink


1. PART A - Mineral Resources

The main types of mineral deposits in the marine environment currently being considered for

exploitation are SMS-deposits, Mn-nodules and Co-rich crusts. In Norwegian waters the main

focus has so far been on SMS deposits. Seafloor massive sulphide deposits generally contain

metals such as Fe, Cu, Zn, Pb, Ag and Au, and are found in both active and extinct

hydrothermal systems. Hydrothermal systems are associated with plate boundaries at Mid-

Ocean Ridges, volcanic arcs or at back arc spreading centres (e.g. Rona 2008; Hannington et

al. 2011; Hoagland et al. 2010). They form when seawater circulates through the seafloor and

reacts with the surrounding rocks. The seawater is heated by an underlying magmatic source

and may reach temperatures above 400°C. Due to the increased temperature the fluids will

rise towards the seafloor, and when the warm fluids meet the cold seawater the dissolved

metals precipitate as metal sulphides (e.g. Rona et al. 1987; Alt 1995; Wheat and Mottl 2000;

Kelley et al. 2002; Früh-Green and Bach 2010). This precipitation process occurs either at the

seafloor as chimney-like structures or below the seafloor. There are several types of systems

depending on geological setting, depth and the temperature of the hydrothermal fluids. In

general deep and high-temperature systems have higher concentrations of Cu. At present

there is no commercial exploitation of SMS deposits. However, Nautilus Minerals expect to

start mining the Solwara 1 hydrothermal deposits outside Papua New Guinea in 2018.

The first discovery of a deep-sea hydrothermal vent and its associated life was in 1977 at the

Galapagos Rift (Lonsdale 1977), leading to a renewed interest for deep-sea biology, which

today is a very vibrant field of research. Hydrothermal vents and organic falls are ephemeral

habitats that are colonized by organisms relatively fast (Vrijenhoek 1997). Their temporal

nature is dependent on the underlying geology, and while some vents are fairly recent, other

vent areas have existed for several tens of thousands of years. Organisms living there are

adapted to the low stability and the ephemeral nature of the hydrothermal vents (and other

reducing habitats) (e.g. Smith et al. 1989; Vrijenhoek 1997). Hydrothermal vents are of

ephemeral nature as venting may cease because of changes in tectonic activity. From an

evolutionary perspective there seems to be a quite rapid adaptation of organisms to a life at

hydrothermal vents. This is possible because most invertebrates have a short life span and a

short reproductive cycle (or reproduce often), and a single vent site that has existed only a

brief moment in geological time scale has served as a stable habitat for perhaps thousands of

years or generations. Hydrothermal vents are of different age; while older ones over time

become less active and colder, new ones are established and a new colonisation process

starts. Each vent can be considered a stepping-stone in the colonisation process, and e.g.

Smith et al. (1989) and Tandberg et al. (2013) also include fall biota and cold seeps among

the stepping-stones because of the somewhat similar reducing conditions. The temporal

overlap between these stepping-stones makes it possible to maintain deep-sea

chemosynthetic ecosystems in an area in spite of the relatively short lifetime for each

“stone”. The adaptation and specialization at hydrothermal vents is made possible by some

key factors. First is the temporal overlap mentioned above, i.e. a new vent or fall is

colonized before the first becomes extinct.


Secondly, that reducing habitats1 are widespread, even though hydrothermal vents are normally

located along mid-ocean ridges. Thirdly, that many of the organisms have life history strategies

and adaptations supporting pelagic transport (high genetic connectivity), so that they are

always potentially ready to colonize new sites regardless of the instability within individual

sites. The key to continuity is nevertheless a sufficient number of suitable hydrothermal

habitats within an area reachable by larvae, and continuous supply of new large falls such as

e.g. whales and tree trunks.

Thus, if we can consider the vents to be biologically stable even though vents are ephemeral

we then need to ask what role the vents do play in a broader perspective such as e.g. plankton

life history and if for instance they may be a buffer against the low organic input during the

low productive season? Are hydrothermal vents and other chemosynthetic ecosystems housing

unique, isolated niches for small and fragile assemblages of biota, or are they part of a larger,

vital community that is able to provide the stability needed over time for genetic adaptation

and endemism? Do the vent organisms illustrate that marine invertebrates in general are

resilient to rapid environmental changes or are the vent adapted animals rather the exception?

And more importantly, are the vent communities resilient enough to resist the extra impact

that mining may represent? These are important environmental questions that are concerning

both scientists, management bodies and the general society, and this report aims to give a

short summary of current status of knowledge, identify knowledge gaps, and to pinpoint the

most important concerns to be taken into consideration in the context of mining of deep-sea

mineral deposits in Norwegian waters.

1 Reducing/chemosynthetic habitat: environment that contains reduced abiotic chemical

species like methane and sulphides which chemotrophic microorganism can convert to organic

energy.


1.1 Geographical location of known mineral

resources of potential commercial value in

Norwegian waters Several active and inactive hydrothermal systems have been discovered along the Arctic Mid-

Ocean Ridge (AMOR) (Pedersen et al. 2010a, 2010b). These vent fields are located within the

Norwegian EEZ or at the Extended Continental Shelf. So far two inactive and four active

hydrothermal systems with potential mineral resources have been detected at the Kolbeinsey-

Ridge and the Mohns- and Knipovich Ridges (Table 1, Figure 1).

Table 1 Known active vent fields with associated Seafloor Massive Sulphide-deposits (SMS-deposits) along the Arctic

Mid-Ocean Ridge.

SMS-deposit

locality

Year of

discovery

Hydrothermal Vent

Field

Ridge Depth SMS-deposit

locality

Troll Wall 2005 Jan Mayen Vent Fields

(JMVF)

Mohn Ridge 500 meter Troll Wall

Soria Moria 2005 Jan Mayen Vent Fields

(JMVF)

Mohn Ridge 700 meter Soria Moria

Loki's Castle 2008 Loki's Castle Vent

Field (LCVF)

Knipovich Ridge 2400 meter Loki's Castle

Perle and Bruse 2013 Jan Mayen Vent Fields

(JMVF)

Mohn Ridge 500 meter Perle and Bruse

Seven Sisters 2013 Seven Sisters Vent

Field (SSVF)

Kolbeinsey

Ridge

140 meter Seven Sisters

These vent systems are found in a range of environmental settings, ranging in depth from 140-

2500 m depth and with vent fluids ranging in temperature from few degrees to 320°C.

The systems are found both along faults and on volcanic structures, and so far purely basalt-

hosted systems as well as basalt-hosted systems with sediment influence have been found.

There are, however, indications for several unexplored active hydrothermal vent fields along

the Mohns- and Knipovich Ridges (chemical indicators have been detected in the water column),

and it is also likely that a number of extinct fields are present in the same area.


Figure 1 Map of known locations of SMS-deposits within the Nordic Seas and along the Arctic Mid-Ocean Ridge

(AMOR), which is shared between Norwegian and International waters. The lines indicate the EEZ of Norway and

Svalbard.

There is also potential for finding vent fields in a range of different settings, including systems

related to ultramafic rocks and sediment-hosted systems along the AMOR. At present there are

no well-documented quantitative estimates of the mineral resources associated with any of

these systems in the Norwegian waters. Existing resource estimates are not based on empirical

studies.


1.2 Seafloor Massive Sulphide-deposits – Vent

sites, threats and environmental impact

1.2.1 Vent sites Seafloor Massive Sulfides (SMS) discovered this far in Norwegian waters are located at the

northern Kolbeinsey Ridge and along the entire Mohns Ridge that define the central parts of

the Arctic Mid-Ocean Ridge system (AMOR) (Pedersen et al. 2010b). Within this area there are

six confirmed active hydrothermal systems. Four of these are within the Norwegian EEZ, one

within the fishery protection zone of Svalbard and one is located at the Extended Continental

Shelf at the central part of the Mohns Ridge. These six sites cover a wide geographic range as

they are spread from Eggvinbanken at the northern Kolbeinsey Ridge in the southwest, and

from the Jan Mayen area north-eastwards along the Mohns-Ridge to the southernmost part of

the Knipovich Ridge. There is great variation in depth and oceanographic settings for the

different sites. The fluid composition is also highly different between sites, resulting in a large

variation in the composition of the SMS-deposits. A summarily description of the different sites

is presented below.

The Seven Sisters Vent Field (140 meters depth Seven sisters vent field (SSVF) is found on the Kolbeinsey Ridge (Figure 1). It is a shallow (~140

m), relatively high temperature system (~200°C) hosted in mafic volcanoclastic rocks. It is

suggested that the mineralization is the result of magma-dominated processes with signatures

atypical from those usually found in a slow-spreading mid-ocean ridge setting (Marques et al.

2015). Sulphide minerals (marcasite, pyrite, chalcopyrite and sphalerite) are present in minor

amounts (often


The Jan Mayen Vent Fields (550 meters depth) The Jan Mayen vent field area (JMVF) is located at the Mohns Ridge at 71°N (Figure 1). It

consists of at least three high-temperature vent fields: Soria Moria, Troll Wall and Perle and

Bruse. The fields are found between 500 and 700 m depth and are of the white smoker type.

The emanating fluids have temperatures up to 270°C, pH between 4.1 and 5.2 and high CO2

contents (Pedersen et al. 2010b). The Troll Wall is the largest of the systems and is located in

talus deposits along a fault at the eastern margin of a rift valley at approximately 550 m depth.

It consists of at least 10 major active sites, each contain several chimneys, which are 5-10 m

tall. The chimneys contain minor amounts of sphalerite and pyrite (Pedersen et al. 2010b). A

diffuse, low-temperature (7°C) venting area, about 500 m west of the high-temperature

venting, is characterised by a large number of iron-mounds that are deposited on top of

hyaloclastite and basaltic debris in the rift valley (Möller et al. 2014). The Soria Moria is located

in lava flows at the top of a volcanic ridge at about 700 m depth, and consists of at least two

different venting areas with several 8-9 m tall chimneys (Pedersen et al. 2010b). The chimneys

contain minor amounts of pyrite, phalerite and galena. The Perle and Bruse consist of two areas

with several chimneys. The chimneys contain minor amounts of pyrite, sphalerite and galena.

No resource estimates of the deposits have been made for any of the Jan Mayen Vent fields.

The JMVFs have a mixed hard and soft substrate with variable topography. The fauna of the

Troll Wall and Soria Moria fields is a relatively well described in Schander et al. (2010). These

vent fields, which were the first fields discovered at the AMOR (2005), are also the most

visited/investigated fields in Norwegian waters. The discovery of a third field in 2013, The Perle

and Bruse indicates that that our knowledge is limited in spite of frequent scientific cruises.

Moreover, there are also organisms found only once suggesting differences within a short range

and that we have not reached an asymptote regarding species richness. The overall fauna

composition is nevertheless similar throughout the field with natural variation according to

substrate, inclination and temperature. Apart from the bacterial feeding Gastropods Skenea

spp. and Pseudosetia griegi as well at cladorhizid sponges the fauna is dominated by typical

bathyal species from the surrounding waters (Schander et al. 2010; Sweetman et al. 2013)

(Figure 3).


Figure 3 Remotely Operated Vehicle (ROV) images from the Jan Mayen Vent Field (JMVF) (A-G). A. White smokers on

the Soria Moria vent field. B. Chimneys covered by a dense mat of Beggiatoa-like bacteria. B’. A juvenile of Skenea

sp. from the bacterial mats. Note the filamentous bacteria growing on the shell. C. Typical vertical rocky surface

just some meters away from the chimneys. These surfaces are covered by large anthozoans (Hormathia sp. (h) and

others), several species of cladorhizid sponges (cl) and the hydroid Corymorpha groenlandica (co). D. The crinoid

Heliometra glacialis form dense aggregations surrounding the vent fields. E. Unidentified cladorhizid sponge found

growing directly on a smoker. F. Sycon abyssale, one of the calcareous sponges common in the area. G. Corymorpha

groenlandica (co) and a cladorhizid sponge (cl) hanging on a vertical surface. H. Pseudosetia griegi without bacterial

filaments (SEM photo) (from Schander et al. 2010).

The Ægir’s Vent Field The Aegirs Vent Field (AVF) was discovered in 2015 at 2200 meters depth at a volcanic ridge on

the central Mohns Ridge. At present the only data collected is video footage and rocks for

geological/geochemical characterization, and no data have so far been published from this vent

field. Based on the very limited video footage available, the field appears quite similar in

appearance regarding the fauna when compared to the Loki’s Castle, but different from more

shallow vent sites in the area (Figure 4). The amphipods observed close to the diffuse venting,


and even close to the summit of a chimney, may be similar to one observed at the Loki’s Castle

Vent Field (LCVF), and the fish also seems similar to those that are found at LCVF. Due to the

depth one would expect even more similarities with Loki’ Castle, but it appears quite different,

probably because there are no sedimentary areas with Sclerolinum fields at AVF.

Figure 4 These are the first images from the Aegir’s Vent Field (AVF) discovered in 2015. In the upper part of the

figure it is possible to see an amphipod close to diffuse venting (unknown temperature). The lower right part shows

a fish (an eelpout) similar to those known from Loki’s Castle Vent Field. This fish was highly abundant at this site.

The lower far left part shows an overview of one the chimneys (approximately 10 m tall). The blue circle

corresponds to the location of the fish and amphipods in the figure.

The Loki’s Castle Vent Field Lokis’s Castle is located at 2400 m depth at 73° N, 8°E at the Mohns Ridge-Knipovich Ridge

transition at the crest of an axial volcanic ridge. It is a black smoker system with 5 chimney

structures that are up to 11 m tall. The emanating fluids have temperatures up to 320°C, a pH

of 5.5 and a chemical composition that indicates influence of buried sediments, probably from

the Bear Island fan. The main sulphide minerals are sphalerite, pyrite and pyrrhotite. There

are also minor amount of chalcopyrite present in the chimneys. A diffuse low-temperature

venting area with numerous up to 1 m tall barite chimneys located on the eastern flange of the

sulphide mound. The temperature of the fluids in the barite field emanating from the active

chimneys is up to 20°C (Eickmann et al. 2014; Steen et al. 2016).

The discovery of Loki’s Castle is perhaps the most ground-breaking discovery made during the

investigations along the AMOR so far. It was the first black smoker vent system ever found on

an ultraslow spreading ridge and it represented the first record of true vent-endemic


macroorganisms along the AMOR (Pedersen 2010a, Tandberg et al. 2011, Kongsrud and Rapp

2012). The fauna is different from the surrounding deep-sea of the Nordic Seas and a

preliminary characterization of the field suggest two zones; 1) black smoker chimneys with

microbiota, but also with gastropods and amphipods, and 2) low-temperature venting with

barite chimneys. The first is a hard substrate where the fauna is sparse in biomass, highly

variable in abundance and generally low in diversity. The second is primarily a soft bottom

habitat with a rather diverse and abundant fauna that is characterized by siboglinid tubeworms

(Sclerolinum contortum), amphipods, gastropods and tube dwelling polychaetes (Pedersen

2010a, Tandberg et al. 2011, Kongsrud and Rapp 2012) (Figure 5). A complete inventory is on

its way (Rapp et al. in progress).

Figure 5 Remotely Operated Vehicle (ROV) images from the Loki’s Castle (LCVF). A-B illustrate the low temperature

barite field, C illustrates a hydrothermal chimney and the vent amphipod Exitomelita sigynae. D shows an scanning

electron microscopy (SEM) image of the gills of Exitomelita covered by sulfur- and methane oxidizing bacteria and E-

F show dense aggregates of polychaetes and gastropods at the base of a chimney (Pedersen et al. 2010a).

The Copper Hill

The Copper hill is a massive sulphide deposit located at 72°N, 2°E, at a mineralized fault

zone at the NW side of a rift valley at around 900 m depth. Some of the matrix-supported


fault breccias dredged from the area are heavily mineralized and may contain up to 30 modal

percent sulphides. The most abundant sulphide is chalcopyrite (Pedersen et al. 2010b).

There is no biological information from this location.

The Mohn’s treasure

The Mohn’s Treasure is a massive sulphide deposits located at 2600 m depth on the Mohns

Rigde (73°N, 7°E). It is found at the edge of an inner rift wall suggested to be a mass-wasting

feature composed of partly lithified sediment. It consists of fine-grained porous chimney

fragments with fluid channels and is predominantly composed of pyrite.

There is no biological information from this location.

1.2.2 Threats and environmental impact Basically mining consist of 1) physical intrusion in the habitat using large sized machinery, 2)

transport of the cut rocks in a slurry towards the surface using a riser (pipeline), 3) dewatering

on board the mining vessel and 4) transport the sulphides to a shore based treatment plant.

The mining processes will expose sulphidic minerals to the oxic seawater. When sulphides are

exposed to the oxic water they will oxidize and might release heavy metals to the environment.

The sulphides will be exposed in scars where sulphides are removed in the mined area, in

plumes of sediment that are up-whirled during the mining process and in plumes of very fine

particles (< 8µm) released in water returned to the seafloor from the dewatering process. The

water from the dewatering process may, in addition to fine particles, contain chemicals that

potentially can be harmful to the environment. The plume might spread to a relatively large

area surrounding the mining site, depending on the current conditions.

Threats and environmental impact from deep-sea SMS-deposit mining are categorized as direct

and indirect. Direct impacts are the immediate loss of habitat (flattening of the 3D structure)

and killing of organism by the machinery and smothering, while indirect effects include

mechanical stress from sedimentation and biochemical stress through release of toxic metals

to the water column (will affect both the benthic and pelagic system). The response of an

ecosystem and individual species to these threats, alone or cumulative, is defining the

vulnerability of the habitats.

Direct impact

o Physical destruction of the habitat.

o Smothering of organisms

Indirect impact

o Mechanical stress from sedimentation and fine grained particles in the plume

o Biochemical stress from toxic metals

Habitat vulnerability

Hydrothermal systems are considered to be adapted to frequent disturbance because of their

ephemeral nature and location in regions of frequent earthquakes. The key to adaptation to a

changing environment is an organisms’ generation time or reproductive cycle. A resilient

community is less vulnerable, but resilience depends on degree and character of disturbance,

species composition and larval supply (Allison 2004).


Even though re-recruitment (genetic connectivity) depends on several factors that are linked

to life strategy and dispersal capabilities (Boschen et al. 2013, Van Dover 2011), perhaps the

most important factor, when mining causes disturbance, will be presence of nearby populations

that secure supply of larvae. Subsequently, vents populated by fauna commonly found in

adjacent waters will likely be re-populated quite fast after disturbance as long as the substrate

is still suitable for settlement of larvae. One can therefore expect that both SSVF and JMVFs

are potentially less vulnerable in terms of chance for re-colonization compared to the Loki’s

Castle and Ægir’s Vent Field. Vents with more vent-specific fauna like at Loki’s Castle are on

the other hand expected to have a much lower potential for being re-colonized and the impact

of mining may be much more severe on the endemic fauna in the region. Furthermore, response

to threats (e.g. heavy metals) may be taxa-specific because of different reproductive

strategies, larval dispersal potential, regional and local population density and

competitiveness. Thus, tolerance of toxins (e.g. Kádár et al. 2005) and genetic connectivity

will be important when one assess vulnerability. However, presently there are no published

toxicology or connectivity studies regarding fauna from AMOR.

1.3 Environmental considerations and

restitution potential

1.3.1 Before mining At present no habitat vulnerability assessments have been conducted for vent systems and SMS

deposits found along the AMOR. However, available information from other SMS-deposits and

hydrothermal vents along the Mid Atlantic Ridge (MAR) as well as the Pacific may prove useful

also for the AMOR systems. Nevertheless, as all vent systems have their own

biological/biogeochemical characteristics, and are found in different geological and

oceanographic settings, site-specific investigations should be conducted.

Short list of pre-mining tasks

Biodiversity inventories

Seasonal data (biology, geochemistry)

Time series (biology, geochemistry)

Settlement and re-recruitment experiments

Connectivity studies of key taxa (by use of molecular tools)

Oceanographic data (hydrography and current regime)

Establish monitoring parameters

Test mining

Applying a precautionary approach is an obviousness when planning activities with a potential

negative impact on the environment. In general that requires that thorough baseline studies

are made prior to these activities. Baseline studies prior to SMS mining should also include

localities beyond the actual ore, and mapping of the surroundings of the SMS-deposit in question

will be important in order to be able to evaluate re-colonization from neighbouring

populations/locations. Connectivity studies have proven important and are commonly used.

Furthermore, the baseline would need to include hydrographical conditions in a large area

surrounding the mining locality in order to be able to model and predict the extent of potential

impact of both the mining/crushing activity itself as well as the dewatering process.


Species composition and community structure are highly important (and fundamental) elements

in both the baseline studies and the later impact assessment. Furthermore, long-term studies

are crucial to understand seasonal changes and natural fluctuations in species composition at

these sites. Such studies will make it possible to distinguish changes that are due to mining

impact from natural changes and fluctuations. At present there have been no quantitative or

long term studies in these systems, and there is no information about the natural seasonal

variation from any vent system or inactive SMS-deposit in our waters. Furthermore, there is no

information published of larval development, reproduction period or distribution and settling

of larvae on the AMOR hydrothermal vents (or SMS-deposits).

Solid data on hydrographical conditions will furthermore be important in order to model

dispersal of the plume of fine-particulate matter from discharge water as well as the physical

mining activity on the seabed. Natural sedimentation rates are not known from any of the AMOR

localities and a base line with seasonal data should be established. Hydrographical data will

also contribute to knowledge of directionality of connectivity between populations at

neighbouring sites. However, gaining good hydrographical data from the Mohns Ridge appears

to be complicated as the ridge is in the intersection of several deep-sea basins with very

different water masses, as well as due to the very rough topography of the ridge and a

complicated current regime. Observations of the plume at Loki’s Castle have shown that the

directionality of the plume is highly variable and long-term monitoring is therefore

recommended.

Inventories and experiments (in-situ and laboratory) are useful, but a test mining should at

some point be advised in order to test models, predictions, hypotheses and direct effects.

1.3.2 During mining Monitoring will probably be the most important measure. However, methods for monitoring

have to be established prior to mining as well as defining monitoring parameters. Existing

methods and experience from monitoring impact of bottom fisheries and oil exploitation may

to a certain degree be applied, but as additional challenges and impacts are expected, a more

specialized monitoring program should be developed to cover deep-sea mining.

Secondly, from the knowledge acquired from the pre-mining studies one should establish mining

methods for minimal impact on the community. In each area subject to mining certain areas

should be kept undisturbed to secure fast re-colonization. In the case of single, isolated vent

communities with a site-specific fauna mining should be avoided.

Short list of pre-mining tasks

Continuous monitoring

Neighbouring protected areas

1.3.3 Restitution potential Restitution depends on several factors. These are linked to the impact and the resilience of the

community. From a general point of view localities that have species commonly found in the

surrounding waters will be re-colonized faster than localities with a vent-specific fauna (or

even site-endemic fauna). The Jan Mayen Vent Field and SSVF are examples of localities that

we expect to be quite resilient, while LCVF and ADVF hosts a much more specialized fauna with

a very limited known distribution and may therefore be much more vulnerable. Furthermore,

restitution potential is also linked to conditions left behind after a mining operation. The


topography will be changed, and hard substrate that used to be peaks and moulds of old

chimneys kept clean by currents, may now be flattened with an accumulation of soft sediments

that are not suitable for a specialized vent fauna. The remaining sediments may also be

unsuitable for organisms due to toxicity (particles from SMS-deposits are highly reactive).

Potential for restitution is therefore expected to be highly variable and site specific.

1.4 Knowledge status and mapping Mineral resource mapping is limited to the habitats mentioned in chapter 2. Other resources

are likely to exist along AMOR and the Jan Mayen Ridge between Iceland and Jan Mayen

However, no proper quantitative resource estimates have been made in any of the known

localities so far and accurate resource estimates are therefore not possible to make with

existing data. Attempts to make rough estimates on the volume and value of the deposits in

Norwegian waters have been made, but until more thorough studies have been made these

estimates should be treated with care.

Biological knowledge status is limited to the localities from chapter 2. Of these the Jan Mayen

Vent Field is the most thoroughly studied site and the main datasets have been published. The

Loki’s Castle has by far the most specialized fauna and it has now been sampled adequately.

Parts of the data are already published and a full review of the diversity, trophic

interactions/ecology and connectivity of this fauna is in progress (Rapp et al. unpubl). The

remaining vent sites are heavily undersampled and there is at present only limited information

about these sites. Ecological studies are few and are limited to a preliminary JMVF food web

study (Sweetman et al. 2013) and a species-specific plume food web study (Olsen et al. 2013).

There are so far no published studies on the community structure of the vent fauna, but there

are some studies of the microbial communities at JMVF and LCVF, covering both the benthic

and pelagic parts of the vents (Jaeschke et al. 2012; Steen et al in press; Olsen et al. 2014).

There are very limited hydrographical data available. However, geochemical data have been

published from some sites and more are in progress (Stensland 2013; Baumberger 2011;

Thorseth et al in prep).

All information above concerns active hydrothermal vents, while there is very limited data

available for the two inactive sites registered so far. In our waters we may divide the vent

communities/fauna in three major types: 1) Species/fauna shared with non-vent habitats in the

surroundings and fauna not depending on chemosynthetic production (majority of the taxa

encountered at SSVF and JMVF), 2) a community with vent-specific species depending on

chemosynthetic production and 3) a community adapted to inactive hydrothermal sites (Dover

et al. 2011). The inactive sites in the Norwegian waters remain unstudied, and as mining activity

will most likely mainly be confined to inactive sites, this lack of knowledge calls for new and

comprehensive surveys in inactive areas.

More information and details about the biology of the various SMS-deposits/vents can be found

in the publications listed below each site:

Seven Sisters Vent Field (140 meters depth) Marques et al. 2015.


Jan Mayen Vent Field (550 meters depth) Pedersen et al. 2010; Schander et al. 2010; Lanzén et al. 2011; Olsen et al. 2013, Sweetman

et al. 2013; Olsen et al. 2014.

Ægir’s Vent Field No data published

Loki’s Castle Pedersen et al. 2010; Tandberg et al. 2011; Kongsrud and Rapp 2012; Jaeschke et al. 2012;

Jorgensen et al. 2012; Dahle et al. 2013; Olsen et al. 2013; Olsen et al. 2014; Spang et al.

2015; Jørgensen et al. 2015; Stokke et al. 2015; Dahle et al. 2015; Georgieva et al. 2015;

Steen et al. 2016; Kongsrud et al. submitted manuscript.

Copper Hill No data published

Mohn’s treasure No data published

Pelagic and plume communities Pelagic data is not within the scope of this report, but plumes are important links to the pelagic

community and data from hydrothermal plume suggests that there is an aggregation of biota,

probably because of increased production. The initial hypothesis about the AMOR plume

communities suggested that it would be different compared to the background regarding

diversity and abundance of organisms. This working hypothesis was based on similar patterns

observed in Pacific hydrothermal plumes (e.g. Van Dover 2000). Echo sounder images

(unpublished) at JMVF showed indications of higher abundances of mesopelagic fish and

plankton above vents. Present results show, however, that the plume communities are not vent

specific. Instead they may be more similar to the background community (Olsen et al 2014,

unpublished data). However, good quantitative data are not available for AMOR hydrothermal

plumes. Regardless if the pelagic biological communities are more specialized or more

abundant compared to the surroundings, they will possibly be affected negatively by discharge

water particles. Thus, plankton should be considered equally important as the benthic

community. Plankton act like a natural link to higher trophic levels, and bioaccumulated heavy

metals released through the mining process will be brought to higher trophic levels in the food

chain.

Summary of knowledge gaps:

Inventory and baseline

o Full biodiversity inventories are at present lacking for most known sites

(except JMVF and in part LCVF). Inter annual variation (base line data) in

faunal composition and abundance remains largely unknown

o The extent of hydrothermal activity in parts of the area is largely unknown

and therefore it is at present not possible to designate “protected areas”

between mining sites to ensure that endemic fauna is not lost and to make

recolonization of mined areas possible.

o Studies of the planktonic community surrounding vents and in the plumes

are at present very limited

o No studies have been conducted on inactive sites

Connectivity/phylogeography/biogeography

o Although the first studies on the connectivity and phylogeography of Arctic

vent- and seep fauna have been initiated there is really a long way to go


before any conclusions can be made on the origins of this fauna, the degree

of connectivity between sites at a local and Ocean scale, and what are the

most important biogeographic drivers shaping the fauna composition in

Arctic vents.

Seasonal data

o Sedimentation rates (both from above and because of sedimentation of

the hydrothermal plume) are unknown.

o No data on reproduction and timing of larval settlement

Experimental data

o At present there are no proper in situ studies on e.g. re-colonization or

mining-sediment exposure.


2. PART B - Gas hydrates

Methane hydrates are structures where methane molecules are surrounded by a lattice of

water-ice molecules in a cage structure (e.g. Englezos 1993; Sloan 1998; Koh et al. 2011). They

are stable under specific temperature and pressure regimes where there is a sufficient methane

supply (e.g. Kvenvolden 1993). This zone is referred to as the gas hydrate stability zone (GHSZ).

Gas hydrates are primarily found in two areas; continental areas, including continental shelfs,

where the surface temperatures are very low, and in submarine continental slopes and rises

with low temperatures and high pressures (e.g. Kvenvolden 1993). The most common way of

identifying potential methane hydrates in marine environment is through the detection of

bottom simulating reflectors (BSR) in reflection seismic data (e.g. Buntz et al. 2003) that

represents the transition between methane hydrates and free gas in the sediments.

Gas hydrates are often found in areas with hydrocarbon rich fluids seepage, also known as cold-

seeps. Cold-seeps have been known for more than 30 years from most parts of the world oceans,

and are associated with chemosynthetic fauna (Decker et al. 2012). Geochemical conditions

are important contributors for the formation of the habitats of with this fauna, which is quite

similar to what is found on hydrothermal vents. Unlike hydrothermal vents, that have a

restricted radius, cold-seeps and the associated fauna are commonly found over larger areas.

Due to the wide distribution of cold-seep faunas, gas hydrate exploitation may have different

impact compared to mining of SMS-deposits. The physical impact itself is also assumed to be

less extensive and will resemble more an oil drilling operation instead of a complete removal

of the crust. In addition, some cold-seeps and gas hydrate areas are already relatively well

studied and the habitats and communities at different sites bear more in common over a quite

large geographic scale, suggesting that gas hydrate exploitation may be less controversial than

deep-sea mining of SMS-deposits.

2.1 Geographical location of known gas

hydrates of potential commercial value in

Norwegian waters

Methane hydrates is a potential future energy source and it has been suggested that there is

twice as much gas in hydrates as there is in all other hydrocarbon reserves combined (Koh et

al. 2011). At present there is no commercial scale production of methane hydrates, but

production tests have been initiated and commercial scale production is expected to start up

before 2020 in Japan and Canada (Collett et al. 2015). However, there is no complete

information available on the value and size of the resources present in Norwegian waters.

Within Norwegian waters there are confirmed gas hydrates along Nyegga, Storegga


Figure 6 Map showing the areas of gas hydrates. The lines indicate the EEZ of Norway and Svalbard.

2.2 Gas hydrate habitats, threats and

environmental impact

2.2.1 Habitats Our knowledge about the gas hydrate habitats are linked to our knowledge of the cold-seep

communities that coincide with three or possible more of the gas hydrate localities in this

report. The cold-seep habitats are soft bottom habitats, however, recent studies characterizes

them according to the biological communities they host instead of physical variables (Decker

et al. 2012). The rationale for using biological communities instead of a stringent physical

characterization is because of the biogeochemical link between the gases and the microbial

communities. Specific bacterial taxa are adapted to utilize specific geochemical conditions,

like for instance methane (or sulphide rich fluids), and eukaryotic fauna (e.g. >500 um) may in

turn use the microbial flora in symbioses or through grazing, and the continuous supply of fluids

maintains the community (Decker et al. 2011). Thus, the habitat is defined from the

geochemical conditions rather than depth, sediment particle size, inclinations etc.


Furthermore, geographically separated localities are similar because these similar geochemical

conditions support similar microbial communities associated with the same symbiotic fauna. In

other words, at these localities, geology, microbiology and macro/mega fauna are strongly

linked. Because of the lack of site specific fauna (with some exceptions) and similarities

between the geographical localities the gas hydrate areas are treated as a whole in the

remaining part of this report.

Håkon Mosby mud volcano, Storegga, Nyegga, SW Barents Sea and Vestnesa Ridge, west

Svalbard margin In Norwegian waters gas hydrate resources have been reported from the Nyegga/Storegga,

Håkon Mosby Mud Volcano (HMMV), SW Barents Sea and Vestnesa Ridge along the Svalbard

western margin (Figure 6).

The Nyegga and Storegga area is located on the Mid-Norwegian margin at the border between

two large sedimentary basins; the Vøring basin and the Møre basin (Bouriak et al. 2000; Bunz

et al. 2003; Zillmer et al. 2005; Hovland and Svendsen 2006). Gas hydrates in the area are

inferred from BRS identification in an area between ~64.7 and 65.3°N, 4 and 6°E (Bouriak et

al. 2000; Bunz et al. 2003; Zillmer et al. 2005). The Nyegga area is the only area within the

Norwegian waters for which an estimation of in-place gas resources has been made (Senger et

al. 2010).

Håkon Mosby Mud Volcano is located on the Norwegian-Svalbard continental slope (western

Barents Sea) at 1250-1260 m depth. It is formed within a slide valley that incised the Bear Island

fan. The sediment cover over the oceanic crust is 6 km thick (Hjelstuen et al. 1999). The gas

hydrates at HMMV have been detected through seismic imaging and have also been cored

(Ginsburg et al 1999; Vogt et al. 1999; Pape et al. 2013).

In the Barents Sea, methane hydrates are inferred in several areas in the SW parts from

identification BSR and modelling of the gas hydrate stability field (Laberg and Andreassen 1996;

Laberg et al. 1998; Chand et al. 2008; 2012; Rajan et al. 2013)

The Vestnesa ridge is a >2 km thick sediment drift located at 1000-2000 m depth. Gas hydrates

have not been sampled but a prominent BSR from several seismic studies suggest that gas

hydrates and gas accumulates are common in the area (e.g. Posewang and Mienert, 1999; Plaza-

Faverola et al. 2015).

To our knowledge, no information is published about the biology of the Vestnesa Ridge. Yet,

Centre for Arctic Gas Hydrate, Environment and Climate (CAGE) will expectedly in the near

future contribute to clarify and describe the benthic community as part of their activity at this

and other gas hydrate and cold-seep sites in the area.

Håkon Mosby Mud Volcano is, on the other hand, a well-studied cold-seep and gas hydrate

locality, and are together with Nyegga and Storegga one of the best studied seep localities in

Europeean waters (Decker et al. 2012, Portnova et al. 2014, Gebruk et al. 2003). Decker et al.

(2012) suggested five main zones according to the dominating benthic community at HMMV; 1

- centre of the seep (volcano), 2-3 - bacterial mats, and 4-5 - habitat forming polychaetes of

the family Siboglinidae (Siboglinid-fields of e.g. the symbiotic polychaetes Sclerolinum

contortum and Oligobrachia hakonmosbiensis) (Figure 7). Sclerolinum contortum is also found

at Nyegga and Storegga. The Siboglinid-field habitat supports a higher biodiversity compared

to the both background and the more central, bacteria dominated part of the seep, and the

Siboglinid-fields are similar between geographically distant sites (Decker et al. 2011; Portnova


et al. 2014). Based on this, Decker et al. (2014) suggests that the community structure is

controlled by geochemical conditions rather than geography and depth. Portnova et al. (2014)

came to a similar conclusion based on Nematode assemblages from the Nyegga. Dense

Siboglinid-fields at the low-temperature venting in the barite field at Loki’s Castle, which are

fundamentally different in depth and other physical characteristics, supports the conclusion

that geochemistry is a strong structuring factor of the benthic community (Kongsrud and Rapp

2012, Steen et al. 2016).

Figure 7 Siboglinid fields at Håkon Mosby Mud Volcano (from a Centre for Geobiology cruise in 2009).

2.2.2 Threats and environmental impact The knowledge about how methane hydrates will respond to production activity is limited and

therefore the knowledge about environmental impacts is also very limited. However, as for

minerals the threats may be split in direct (acute) and indirect and it is likely that exploration

of gas hydrates will meet many of the same environmental challenges that are met by the oil

and gas exploration today including impacts from drilling activity and disposal of produced

waters (Moridis et al. 2011). Yet, the major concern is that decomposition of hydrates might

lead to sediment volume change, sediment instability, ground subsidence and slumping (e.g.

Kvenvolden 1994, Lee et al. 2010; Song et al. 2014). This might lead to immediate destruction

of habitats, and indirectly it will lead to large sediment plumes that will affect biological

communities over a large distance. Several submarine slope failures may be connected to

dissolution of methane hydrates (e.g. Maslin et al.1998; Sultan et al. 2004a, 2004b; Nixon and

Grozic 2006; Dondurur et al. 2013).

Direct impact

o Physical destruction of the habitat (at drill site and by sediment slide).

o Smothering of organisms in near surroundings

Indirect impact

o Mechanical stress from sedimentation and fine grained plume

Habitat vulnerability


To the best of our knowledge no studies regarding vulnerability of the cold-seep and gas hydrate

communities exist. However, the fauna is linked to the geochemical conditions and one could

therefore assume that the soft bottom Siboglinid communities will re-emerge if the

geochemical conditions like the flows of hydrocarbon rich fluids continue after impact. Still,

we do not know how long it may take before a re-colonization of the major fauna elements will

happen and if there will be a full recovery of the community. Siboglinid-fields are relative

common, and provided the directionality of the genetic connectivity (larvae drift) is favourable,

re-colonization is not unlikely. To our knowledge no re-colonization, laboratory or in-situ

experiments exist on these Siboglinid fields yet, however experimental investigation is part of

CAGE’s scientific aims. The vulnerability of the associated fauna from within the worm-fields

or the surroundings may not be similarly resilient, and should be considered when assessing

vulnerability.

As for the hydrothermal vents along AMOR, hydrographic conditions are significant because

displacement of sediments (slides) may cause large plumes of fine sediments. These plumes

may also represent a threat to coral reefs, sponge grounds and other potentially vulnerable

nature types in the surroundings. Although coral reefs and sponge grounds are not directly

linked to the cold-seeps they are commonly found on Nyegga and Storegga and these reefs and

grounds are considered as very important habitats for several commercial fish species and they

support a very high diversity of organisms when compared to the surrounding sedimentary

areas. Although both sponges and corals are somewhat resilient to moderate sedimentation

there are thresholds of how much they can handle over time. Common for both sponges and

corals is the slow growth and regeneration, which suggest that they are vulnerable for the

extensive physical stress that a hydrate harvesting and a potential underwater slide may

represent.

2.3 Environmental considerations and

restitution potential

2.3.1 Before exploitation At present no habitat vulnerability assessments have been conducted for gas hydrate resources

found in Norwegian waters. Nyegga, Storegga and HMMV are relatively well studied but gas

hydrate exploitation impact assessments have not been part of these studies. Detailed

inventories and spatial mapping should nevertheless be made along the other gas hydrate and

neighbouring areas as well. Also, a complete inventory along the slope depth gradient should

be included since a slide caused by gas hydrate extraction may cause a large-scale and long-

term impact on wide areas beyond the drill site (both the physical mud/sediment slide and the

plume afterwards). Investigation of the slope/sediment stability will be instrumental before

extraction. The potential size of the slide will dictate impact of sedimentation and the size of

the area that may be destroyed. The size will further suggest what we might expect in terms

of recovery time.

Pre impact tasks shortlist:

Short list of pre-exploitation tasks (overlaps to a great extent those for mineral

deposits)

Species/biodiversity inventories

Seasonal data (biology, geochemistry)


Time series (biology, geochemistry)

Settlement and re-recruitment experiments

Conduct proper connectivity studies of a selection of taxa

Hydrographical data

Establish monitoring parameters

Evaluation of potential sediment volume change and sediment instability

2.3.2 During exploitation Monitoring will be the most important measure.

2.3.3 Restitution potential Since the communities are linked to geochemical conditions it is likely to assume that the

potential for re-colonization and recovery is not so bad in the areas of hydrate extraction.

However, if a slide should occur we have no knowledge of how the large sediment plumes will

affect the surroundings. However, we do not know anything about time scale of the impact and

therefore it is also impossible to give any postulate accurate scenarios for re-colonization in

sediment-affected area.

2.4 Knowledge status and mapping Nyegga, Storegga and HMMV are fairly well mapped and there is some ecological information

available, but a more complete inventory that includes the surrounding (and potentially

impacted) waters is missing. Other known gas hydrate areas are poorly studied. Again, CAGE’s

focus on ecological studies along Vestnesa Ridge will hopefully contribute to fill some of these

gaps of knowledge. Perhaps the most important data that is missing is time series (seasonal

data) and proper baseline studies.

2.4.1 Summary of knowledge gaps

Inventory and baseline

o Full biodiversity inventories are at present lacking for most known sites

(except HMMV and in part Nyegga). Inter annual variation (base line data)

in faunal composition and abundance remains largely unknown

o Studies of the planktonic community surrounding seeps/hydrate areas are

at present very limited

Connectivity/phylogeography/biogeography

o Although the first studies on the connectivity and phylogeography of

Arctic vent- and seep fauna have been initiated there is really a long way

to go before any conclusions can be made on the origins of this fauna, the

degree of connectivity between sites at a local and ocean scale, and what

are the most important biogeographic drivers shaping the fauna

composition in seep- and hydrate areas in our waters.

Seasonal data


o No data on reproduction and timing of larval settlement are available

Experimental data

o At present there are no proper in situ studies on e.g. re-colonization or

exposure of sediments from the extraction process or the more large scale

sediment disturbances expected from potential slides.


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